The requiered sample were not recruited due to COVID-19 pandemic

To evaluate the effect of selective micro-osteoperforations (MOPs) on the amount of distal movement of the upper canine, the mesio-distal inclination of the canine and the messiah movement of the upper first molar.

Methods: Clinical trial with Split mouth design in 35 orthodontic patients with bilateral extraction of the upper first premolar, each upper canine will be randomly assigned to the intervention (MOP) or to the control side. Participants will be followed for 3 months and the investigators will take periapical radiographs, cast models and clinical measurements before and after canine retraction. The measurements will be taken by previously calibrated operators. The results are going to be determined and compared between sides, with the corresponding statistical tests and the results are going to be analyzed.

PICO QUESTION: ¿Does the amount of distal orthodontic movement of the upper canine increase in the side with MOPs compared with the side without MOPs? Population: Orthodontic patients with bilateral extraction of the upper first premolar (Split mouth design trial) Intervention: Distal movement of the upper canine with Selective MOPs (distal to canine) in one hemi-arch Comparison: Distal movement of the upper canine without MOPs in the other hemi-arch Outcome: Canine and first molar movements

GENERAL AIM:

- To evaluate the effect of selective micro-osteoperforations (MOPs) on the amount of distal movement of the upper canine, the M-D inclination of the canine and the mesial movement of the upper first molar.

METHODS

OVERVIEW OF DESIGN Study Design: Randomized controlled clinical trial in split mouth design.

• Randomly assign upper canines in to 2 sides in a split mouth design study: one side to receive intervention (MOPs) and the other side as a control (without MOPs).
• Then follow both sides for three months
• Split mouth design method: The investigators are going to randomly assign to the patients' left or right sides, one side for the intervention and the other side for the control (to eliminate the possibility of selection bias).
• Blinding: It is not possible to blind participants and clinical staff, but the investigators are going to blind the operators who will perform the measurements and the data analysis (single-blinded).

The participants will be with orthodontic fixed appliances (MBT prescription slot 0.022 "x0.028", canine torque 0 °), with working arches 0.019 "x0.025" stainless steel and with bilateral extractions of the first upper premolars for 6 months or more. For this moment the crowding must be resolved and there must be a space of 3 or more millimeters between the canines and second premolars.

The 4 upper incisors will be consolidated with a 0.010 "stainless steel ligature below the arch to prevent opening of anterior spaces.

Observation:

• No transpalatal arch (TPA) will be used in any of the participants
• It is going to place a mini-implant in the palate for reference point before the start of the experiment PLANS FOR RECRUITMENT Patients of the Clinic University (UniCIEO) and Antioquia University POTENCIAL CONFOUNDING VARIABLES
• Age
• Sex
• Systemic diseases not reported by the participant

Inclusion Criteria:

• Class I or Class II malocclusion, division 1 (ANB: 0º-5º) with maxillary canines completely erupted with the need for canine retraction.
• Patients in the working phase with MBT prescription, slot 0.022" who have undergone extractions of bilateral upper premolar with more than three months before the time of upper canine distalization and with open space between the canine and the second premolar greater or equal to 3 mm.
• Age range between 14-40 years.
• Probing depth less than 4 mm in the upper canine

Exclusion Criteria:

• Patients with systemic disease.
• Medicated patients (prolonged use of antibiotics, phenytoin, cyclosporine, anti-inflammatory drugs, corticosteroids, systemic steroids, and calcium channel blockers).
• Pregnancy.
• Poor oral hygiene evident in more than two visits.
• Overjet ≥ 6 mm
• SN-GoGn ≥ 38 °
• Radiographic evidence of moderate to severe bone loss.
• Subjects with active periodontal disease
• Patients who smoke.
• Individuals with inadequately treated endodontic problems in the study area.

Individual participant data is going to be share only for statistical analysis